1. Field of the Invention
The subject invention relates to apparatus for use in checking alignment of motor vehicle frames such as those used in automobiles and trucks.
2. Description of Related Art
Various apparatus have been proposed in the prior art for use in checking the alignment of vehicle frames. One such apparatus particularly directed to automobile frames is disclosed in Chartier, U.S. Pat. No. 3,611,575. That apparatus discloses a sling-suspended body carrying a datum member. The sling suspension is provided by a pair of flexible members, disclosed specifically as chains, which rotatably interlock with a pair of meshed gears horizontally disposed on shafts within the body. Where the automobile frame is distorted, i.e., too high or too low, the flexible chain corresponding to the location of the distortion will be too high or too low on one or both sides, depending upon the distortion. Accordingly, frame height errors are detected and corrected.
The Chartier patent exhibits many of the drawbacks generally associated with prior art frame alignment apparatus. Because of the tension applied to the flexible chains, the body tends to slide down the chains, rather than maintaining a set position beneath the automobile frame. If one of the flexible chains breaks, the entire body apparatus must be disassembled and the chain installed in a precise location to maintain equal chain length. If the internal gears are damaged from dirt or metal fragments entering through the chain opening, the unit must be sent out for repairs, and further delay may be occasioned in waiting for new parts necessary for the repairs. Other disadvantages of the Chartier device are that it is restricted to operation in connection with automobile frames and requires cumbersome auxiliary apparatus.